As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users of information is an information handling system. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes, thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use, including such uses as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
An information handling system may include a storage system or storage network that includes some measure of fault tolerant data storage. One example of a fault tolerant data storage system is a RAID (Redundant Array of Inexpensive Disks) storage system. RAID storage systems combine multiple disks into an array of disk drives to obtain performance, capacity, and reliability advantages over other storage techniques, including, for example, a single large drive. RAID Level 5 is an example of a fault tolerant data storage system. A RAID Level 5 storage system is characterized by the striping of data across disks in the storage system. A set of parity bits generated by an exclusive-OR of the data bits is stored on a disk that is separate from the striped data. The parity bits for the respective stripes of data are distributed in the disks of the storage system so that each disk will likely contain both data bits for a stripe of data and parity bits related to some other stripe of data. In a RAID Level 5 storage system, it is typical that no single disk includes all of the parity bits. RAID Level 5 is often referred to as “rotating parity” storage.
Although the parity bits in RAID storage systems provide some measure of fault tolerance, many RAID storage systems include the ability to attach spare disk drives that can be used as automatic replacement disk drives if a disk drive in the RAID storage system fails. These spare disk drives, often referred to as “hot spare” drives, further reduce the risk of irretrievable data loss due to disk drive failure. While hot spare drives are advantageous for data integrity, hot spare drives are wasted resources during normal operation of the RAID storage system: until a disk drive in the RAID storage system fails, a hot spare drive will remain idle. Some storage systems have tried to take advantage of the idle storage space by using the hot spare drives as log devices. When a disk drive in the RAID storage system fails, the hot spare is converted from a log device to substitute storage. However, if the data saved in the storage system are redundant, as in a RAID Level 5 storage system, a log device is not useful. Other storage systems avoid using hot spare drives and instead reserve spare storage space within the RAID storage system for performance enhancement and failure protection. These storage systems restrict the use of the spare storage space to the disk drives in the particular RAID storage system in which it is included, rather than making the spare storage space available to any disk drive that may benefit.